Can my brother (5 years old) with mild autism recover and lead a normal life?

As above : Although this is a chronic condition if he find the rt support and comorbid condition can be treated , he can do ok ...

One doesn't recover : One doesn't recover from autism. But with proper interventions and treatment, good outcomes are possible. Particularly if treatment was begun at an early age.

Think big...: ...Then go try your very best to make a good outcome his reality. It is not however about "recovering", but rather "developing". There are many opportunities to favorably influence and enhance a young child who has been called "mildly autistic". And, there are likely to be new interventions available in the future. Get expert help. And, start right now.

Autism: Early intervention can lead to favorable outcome and better prognosis.

With intervention: Early intervention can make a very big difference in the degree of a recovery from autism. This requires a time intensive educational approach.

Wide range of sympto: Unless he has been misdiagnosed, there is no cure for autism. However those with high functioning autism and Asperger's disorder can live a relatively normal life, socially and vocationally.